PEARL HARBOR, Hawaii — As crew members lined the edge of the Navy guided-missile destroyer, the ship’s whistle sounded. It was 7:55 a.m., the exact time the Japanese began bombing Pearl Harbor 71 years earlier.

Friday’s moment of silence was part of the commemoration that drew some 2,000 people to Pearl Harbor — and many more to events around the country — to mark the anniversary of the surprise attack that killed thousands of people and launched the United States into World War II....